International Journal of Horticulture, 2016, Vol.6, No.22, 1-14
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Watermelon is highly diuretic and contains large amounts of carotenoids (The Associated Press, 2008; Ibrahim,
2011).
Watermelon is cultivated all over tropical climate the largest producers are China, Turkey, Iran, Brazil and USA in
that order. It is widely cultivated in both the rainforest and the humid and dry savanna agroecologies of Nigeria
(Edoma, 2013). Watermelon has been found to the Lycopene leader among fresh produce. When it became clear to
farmers that watermelon is highly beneficial, many have diversified from its subsistence cultivation to commercial
scale. Watermelon requires warm climate and relatively long growing season (Maynard, 2001; Charles, 2005;
Anon, 2006). On wet soils, the sugar content of the fruit is diluted and further internal pressure due to excess
absorption of water could lead to cracking and spoilage of the fruit thus edibility and market yield significantly
reduced (Boyhan and Masiunas, 1999; Lacier and Plummer, 2003). Worldwide, the yield of watermelon ranges
between 5-60 t/ha and averages about 25 t/ha depending on cultivar and cultural practices. Seed yields of
watermelon are 150-400 kg/ha for most cultivars (FAO, 2010).
The high demand of this fruit is not met in the southern part of Nigeria because of the high rainfall covering many
months of the year. However, Okonmah et al. (2011) reported that Sugar baby as adaptable variety for rainforest
agroecology of southern Nigeria. Five watermelon varieties were examined for adaptation to the early and late
rainy season cropping opportunities in addition to their responses to fertilizer types in terms of growth, yield and
nutritional quality in a rainforest ecological zone of Nigeria. The specific objectives are to: examine Varietal and
manurial effects on biomass accumulation, fruit yield and nutritional quality of watermelon varieties and identify
attributes associated with seasonal adaptation and productivity among the tested varieties.
1 Materials and Methods
1.1 Experimental Site and Conditions
Attempts Five watermelon varieties were selected on the basis of contrasting growth duration and fruit yield and
were evaluated for seasonal adaptation and productivity during the rainy and late cropping season of 2012. The
study was conducted at the Teaching and Research Farm of the Federal University of Technology Akure, located
in the rainforest vegetation zone of Nigeria.
The experiments were carried out between June and August, and September to December 2012 for rainy and late
season crop respectively. Pre-planting soil analysis was carried out, and soil samples were collected randomly
from the experimental site, bulked and taken to laboratory for routine chemical analysis. The experimental site
was cleared, ploughed and harrowed before planting, followed by herbicide spraying to control weeds before
planting was done. The experiment was laid out in a Randomized Complete Block Design with three replications.
The experimental site was a field plot measuring 74 by 10 m with an alley way of 2 and 1 m between blocks and
plots respectively. Seeds were sown at a spacing of 1x2 m on 45 plots each measuring 2 by 4 m.
1.2 Source of Experimental Materials and Treatments
The five varieties tested were (Crimson sweet, Charleston Grey, Kaolac, Anderson and Sugarbaby) while the
manures were organomineral fertilizer (OMF) and NPK fertilizer, and the unmanured which is the control. For
each season (rainy and late), treatment consisted of factorial combina tions of five watermelon varieties by 3
manure types in three replications. The Seeds of three of varieties were procured from National Institute of
Horticulture (NIHORT) Kano while two were obtained from Akure. The manures (OMF & NPK) were applied at
5 t/ha and 200 kg/ha respectively at 3 weeks after planting as spot application. The composition of the manure
used is as follows; NPK 15:15:15 and Sunshine organomineral fertilizer OMF, a product of natural compost
fortified with additional amounts of nitrogen and phosphorus in the combination N 3.5%, P2O 2.5% and K2O
1.5%.
